Recent years have seen the spread of electric vehicles that run on electric motors powered by electricity from a charged secondary battery, and quick-charge stands for electric vehicles are being provided in various places where electric vehicles can make a stop to charge their batteries, increasing the driving range of the electric vehicles. However, there are still not enough quick-charge stands, so electric vehicles can run out of battery power before reaching a charge stand. One idea in such cases for rescuing an electric vehicle that has run out of battery power is to restore the electricity supply function that powers the motor of the electric vehicle, much like replenishing a gasoline vehicle that has run out of gasoline.
For example, technology has been proposed in which an electric vehicle is equipped with a separate secondary battery that can quickly charge the main battery. Thus, whenever the vehicle operating condition deteriorates or the vehicle can't be driven due to a decline in the main battery voltage, the vehicle can be restored to a drivable condition by using the secondary battery to recharge the main battery (see for example Patent Document 1).
Another technology that has been proposed is one in which an auxiliary battery that can supply electricity to the battery mounted on the electric vehicle is carried on a wheeled barrow that can be coupled to the rear of the vehicle, enabling the main battery to be charged by the auxiliary battery while the vehicle is being driven to the nearest charge station (see for example Patent Document 2).